1. Field of the Invention
The present invention relates generally to apparatus for isolating a component from mechanical shock and vibration and, more particularly, to such a device which is uniformly effective in all directions and in which the primary application of stress is in compression.
2. Description of the Prior Art
It has been a goal to isolate certain items against mechanical chock and vibration while adequately supporting such items. Because of the generally complex and fragile nature of electronic circuitry and components, electronic equipment is a prime candidate for such a requirement. The prior art is replete with examples of constructions for providing isolative support for a variety of items. Some of these examples are very old, which is a clear indication that the problem has existed for a long time.
Typical of an early construction is Madge U.S. Pat. No. 1,864,080 which discloses a "cushioned" connection tie for the "non-vibration" transmission of an axial force in a manner eliminating metal-to-metal contact. In this instance, a threaded stud has an enlarged head disposed in a housing and embedded in an elastic material, rubber, which fills all the voids in the housing.
Another early concept is disclosed in Thompson U.S. Pat. No. 1,984,193 which discloses a resilient mounting for sewing machines. The resilient mounting utilizes a sleeve cylinder of cork supported in opposed metal caps. As with the Madge construction, it is effective primarily in one direction only.
Geyer U.S. Pat. No. 1,964,432 discloses an engine mount broadly similar to the Thompson construction. Geyer utilizes a flange on a metal sleeve to be isolated, the flange being embedded in a resilient rubber block which is substantially encapsulated within a metal cup.
A more recent engine mount is disclosed in Clem Te Bow U.S. Pat. No. 3,353,771 which provides an engine mounting system utilizing ball and socket type shock mounts. In this instance, balls on either end of a telescoping tube are rollingly engaged with mating metallic sockets. There is no yielding between each ball and its mating socket. The yielding occurs in the telescoping tube and in a resilient pad interposed between the ball and socket shock mount and the engine to be cushioned.
Olson U.S. Pat. No. 3,363,870 discloses a construction utilizing plastic bodies for a variety of uses, including damping. The construction employs gas or liquid filled bubbles contained within an outer skin. However, there is no disclosure or suggestion of providing damping in a plurality of directions. In a moderately similar type of construction, Shanok et al. U.S. Pat. No. 3,455,546 discloses an impact resistant structural ember which comprises a shell composed of a resilient impact resistant material and a core comprising rigid foams, such as styrofoam. Again, there is no disclosure or suggestion in the patent of providing multi-directional absorption of an impact.
It was in light of the foregoing that the present invention has been conceived and is now reduced to practice.